Temperature measurement can be very simple or very complex, depending on your application and requirements. Understanding these platinum RTD specifications is an important first step toward finding the right device. International industrial RTD standards exist only for platinum RTDs.

esistance temperature detectors (RTDs) operate on the inherent propensity of metal to exhibit a change in electrical resistance as a result of a change in temperature. We are all aware that metals are conductive materials. It is actually the inverse of a metal's conductivity, or its resistivity, that brought about the development of RTDs. Each metal has a specific and unique resistivity that can be determined experimentally. This resistance, “R”, is directly proportional to a metal wire's length, “L”, and inversely proportional to the cross-sectional area, “A”: